1. Field of the Invention
The present invention relates to an adjusting method and adjusting mechanism for remedying the coil pitch tolerance and fatigue deformation of an adjustable helical spring, and more specifically to an adjusting method for remedying the coil pitch tolerance and fatigue deformation of an adjustable helical spring used in a shock absorber.
2. Description of the Related Art
A conventional spring has an elastic coefficient determined at the time of production, and is therefore not always useable for different types of machines. As a result, different helical springs must be designed for different machines or different purposes, and it is uneconomical to do so.
To overcome the above shortcomings, the same inventor of the present invention has invented a casing for adjustable helical spring, which was published under Taiwanese Patent Publication No. 436588 on May 28, 2001. The casing for adjustable helical spring disclosed in Taiwanese Patent Publication No. 436588 comprises a male and a female case, and a rotatable element to enable adjustment of the helical spring to different elastic coefficients to meet the requirement of different machines. The helical spring has an end fixedly connected to a seat at a bottom center of the female case, and another opposite end located in the male case. The rotatable element is provided on an external or an internal surface with a plurality of stoppers to contact with coils of the helical spring. When the rotatable element is turned, the number of effective coils of the helical spring subjected to compressive force or tension force is changed to thereby adjust the elastic coefficient of the helical spring corresponding to actual need. With the casing for adjustable helical spring disclosed in Taiwanese Patent Publication No. 436588, the helical spring is more practical for use, and the problems existed in the conventional helical springs could be effectively solved.
While the casing for the adjustable helical spring disclosed in Taiwanese Patent Publication No. 436588 is able to solve the problem existed in the conventional helical springs, it fails to overcome another common problem in the helical springs, that is, the fatigue and deformation of the helical spring caused by using the helical spring over a prolonged time or overusing the helical spring. So, it is desirable to develop a method and mechanism to effectively solve the above problem to reduce the rate of replacement of the adjustable helical spring.